Move a method from IdentifierTable.h out of line and remove the SmallString include.

Fix all the transitive include users.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149783 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 9d849ff..0293527 100644
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -19,6 +19,7 @@
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/ASTMutationListener.h"
 #include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallString.h"
 
 using namespace clang;